I have a 96 Outback with about 180k miles. The engine has around 100k miles on it. When the car is cold, and I start it, after a couple minutes at ~50mph the check engine light starts flashing. If I drive slower ~25mph and let the car warm up before going ~50mph, then the check engine light will not come on. I had the codes pulled today and they were P0301, P0302, and P0400. Any ideas on what could be going on?

It could be that the EGR is sticking when cold. Ensure its working ok. Of course with any misfire, plugs (NGK) Plug Wires (Subaru or NGK) come to mind.

 

Has the gas mileage gone down?

 

Seafoam or a good injector cleaner would also be a good.

 

How do the plugs look?

You need a good old fashioned tuneup.

 

 

 

Then we will see if you still have issues.

Code p0400 could mean you need a new gas cap.

 

Look at the rubber seal on it, likely the rubber is cracked.

 

misfire codes are probably a sign of needing new plug wires.

Code p0400 could mean you need a new gas cap.

The P0400 code indicates an EGR flow problem. Perhaps you were thinking of P0440.

There's some good info on P0400 here:

http://endwrench.com/images/pdfs/Emissions.pdf

Some general info on P04xx codes:

http://www.endwrench.com/images/pdfs/CodesRevealed.pdf

 

 

misfire codes are probably a sign of needing new plug wires.

Yes, P0301 and P0302 are indeed misfire codes, for cylinders #1 and #2. Those are wasted-spark-paired, so bad ignition wires, plugs, or even one of the coils in the pack could be the cause.

The P0400 code indicates an EGR flow problem. Perhaps you were thinking of P0440.

There's some good info on P0400 here:

 

good catch. You are correct.

 

I would check out the EGR solenoid for function